JPH0450248A - Polypropylene-based resin composition - Google Patents

Abstract

PURPOSE:To provide the title composition excellent in the physical properties balance such as for low-temperature impact resistance, surface hardness and rigidity, also excellent in secondary processability such as coatability and adhesivity, comprising a polypropylene-based resin, styrene-based resin and specific modified polymer. CONSTITUTION:The objective composition can be obtained by incorporating 100 pts.wt. of a blend of (A) 60-95wt.% of a polypropylene-based resin (e.g. propylene block copolymer) and (B) 5-40wt.% of a styrene-based resin (e.g. high-impact polystyrene) with (C) 3-35 pts.wt. of a modified copolymer prepared by adding a unsaturated carboxylic acid (derivative) to at least one polymer selected from C1: an aromatic vinyl compound-conjugated diene compound block copolymer, C2: an ethylene-based elastomer (e.g. ethylene-prorylene rubber) and C3: a polyolefin resin. The present composition may be further incorporated with 3-40 pts.wt., based on 100 pts.wt. of the present composition, of a styrene- based elastomer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to novel polypropylene resin compositions, more specifically, to improve the balance of physical properties such as low-temperature impact resistance, surface hardness, and rigidity of polypropylene/styrene resin compositions. This invention relates to a polypropylene resin composition containing polypropylene resin and styrene resin as the main resin components, which has excellent characteristics and has significantly improved secondary processability such as paintability and adhesion. .

BACKGROUND OF THE INVENTION Conventionally, polypropylene has been used as an inexpensive general-purpose resin in many applications such as films, sheets, injection molded products, and blow molded products. However, although this polypropylene has many excellent properties, it has the disadvantage that its uses are inevitably limited due to insufficient rigidity and impact resistance.

Therefore, attempts have been made to blend styrene-based resins with polypropylene in order to improve these drawbacks, but since the two resins lack compatibility, it is not possible to improve the physical properties sufficiently by simply blending them. can't hope for, therefore
Various attempts have been made to improve the physical properties by adding a third component to improve the compatibility. For example, a resin composition containing a polyolefin resin such as polypropylene, a polystyrene resin, and a styrene elastomer made of a styrene-ethylene/butylene-styrene block copolymer (Japanese Patent Publication No. 34782/1982), Polypropylene resin, polystyrene, and styrene-ethylene/butylene-styrene block copolymer or styrene-
A resin composition containing a styrene elastomer consisting of an ethylene/propylene block copolymer (Japanese Unexamined Patent Publication No. 64
-7256), a resin composition containing a polyolefin resin such as polypropylene, a styrene resin, and a styrene elastomer made of a specific styrene-ethylene/butylene-styrene block copolymer (JP-A-1-174550) Public bulletin) etc. have been proposed.

However, although these resin compositions have a good balance of physical properties such as low-temperature impact resistance, surface hardness, and rigidity, they have the disadvantage of poor secondary processability such as M mounting properties and adhesive properties.

Thus far, no polypropylene resin composition has been found that has an excellent balance of physical properties such as low-temperature impact resistance, surface hardness, and rigidity, and also satisfies secondary processability such as paintability and adhesion. is the current situation.

Problems to be Solved by the Invention Under these circumstances, the present invention solves the problem of polypropylene/polypropylene.
A polypropylene resin composition that fully maintains the well-balanced physical properties of a styrene resin composition such as low-temperature impact resistance, surface hardness, and rigidity, and also has excellent secondary processability such as paintability and adhesion. It was made for the purpose of providing.

Means for Solving the Problems As a result of extensive research by the present inventors to develop a polypropylene resin composition having the above-mentioned preferable properties,
Based on this knowledge, we have discovered that the objective can be achieved by a resin composition containing polypropylene resin, styrene resin, a specific modified copolymer, and optionally used styrene elastomer in a predetermined ratio. As a result, the present invention was completed.

That is, the present invention provides (A) polypropylene resin 60
-95% by weight and (B) styrenic resin 5-40% by weight to 100 parts by weight, (C) (i) block copolymer of aromatic vinyl compound and conjugated diene compound, (
b) Modified copolymers 3 to 3 in which an unsaturated carboxylic acid or a derivative thereof is added to at least one selected from ethylene elastomers and (/\) polyolefin resins.
A polypropylene resin composition comprising 5 parts by weight,
The present invention provides a polypropylene resin composition which further contains 3 to 40 parts by weight of (D) a styrene elastomer to 100 parts by weight of this composition.

The present invention will be explained in detail below.

In the composition of the present invention, the polypropylene resin used as component (A) is, for example, a copolymer consisting of an isotactic propylene homopolymer having crystallinity or an ethylene propylene random copolymer having a low content of ethylene units. A substance commercially available as a so-called propylene block copolymer, which is composed of a homopolymerization portion consisting of a propylene homopolymer or a copolymerization portion consisting of an ethylene propylene random copolymer having a relatively high content of ethylene units. A block copolymer of supercrystalline propylene and ethylene, or each homopolymerization part or copolymerization part in this block copolymer, further contains butene-1.
Preferred examples include substantially crystalline propylene-ethylene-α-olefin copolymers made by copolymerizing α-olefins such as , 2-methylpentene-1, and the like.

These polypropylene resins preferably have an MI (melt index) of 5 to 60 g/10 minutes. If the MI is less than 59/10 minutes, the moldability is insufficient, and if it exceeds 60 g/10 minutes, the impact resistance tends to decrease, which is not preferable.

In the composition of the present invention, the styrene resin used as component (B) may be a styrene homopolymer or a copolymer of styrene and a copolymerizable monomer. It may also be a high impact polystyrene reinforced with a rubbery polymer. Examples of monomers copolymerizable with styrene include α-methylstyrene, m-methylstyrene, p-methylstyrene,
Aromatic monohinyl compounds such as p-chlorostyrene, vinyl cyanide such as acrylonitrile, methacrylonitrile, maleonitrile, acid anhydrides of unsaturated dicarboxylic acids such as maleic anhydride, itaconic anhydride, citraconic anhydride, maleimide, N- Examples include maleimides such as phenylmaleimide, esters of acrylic acid and methacrylic acid such as methyl methacrylate and methyl acrylate, and unsaturated carboxylic acids such as methacrylic acid and acrylic acid.

One type of these copolymerizable monomers may be used, or two types of these copolymerizable monomers may be used.
You may use combinations of more than one species.

In addition, high impact polystyrene reinforced with a rubbery polymer is a blend of a rubbery polymer such as polybutadiene rubber, polyisoprene rubber, or styrene-butadiene copolymer rubber with the above-mentioned styrene homopolymer or copolymer. A material obtained by homopolymerizing styrene or copolymerizing styrene and the above-mentioned copolymerizable monomer in the presence of the rubber-like polymer can be used.

The styrene resin of component (B) has an Ml of 0.5 to 20.
A range of g/10 minutes is preferred.

In the composition of the present invention, the polypropylene resin as the component (A) and the styrene resin as the component (B) have a weight ratio of 6.
0:40 to 95:5, preferably 65:3
5 to 90:10.

If the amount of the styrene resin (B) component is less than 5% by weight based on the total amount of components (A) and (B), the rigidity and surface hardness will be insufficient, and if it exceeds 40% by weight. There is a tendency for moldability to decrease.

In the composition of the present invention, component (C) is at least one selected from (a) a block copolymer of an aromatic vinyl compound and a conjugated diene compound, (b) an ethylene elastomer, and (c) a polyolefin resin. As one type, a modified copolymer to which an unsaturated carboxylic acid or a derivative thereof is added is used.

The block copolymer of (a) above consists of at least one polymer block A composed of aromatic vinyl compound units and at least one polymer block B composed of conjugated diene compound units. However, the polymer block B may be partially or entirely hydrogenated. The content of the polymer block A in this block copolymer is desirably in the range of 20 to 80% by weight, preferably 30 to 70% by weight.

In addition, the block copolymer has a number average molecular weight per single block of polymer block A and polymer block B,
each in the range of 5,000 to 200,000, and the overall number average molecular weight is io, ooo to 400,000.
It is preferable that the ratio of weight average molecular weight/number average molecular weight is in the range of 1.0 to 10.

Examples of the aromatic vinyl compound forming the polymer block A include styrene, alkylstyrenes such as α-methylstyrene, p-methylstyrene, and pt-butylstyrene, and p-methoxystyrene and vinylnaphthalene. Among these, styrene and p-methylstyrene are particularly preferred. One type of these aromatic vinyl compounds may be used, or two or more types may be used in combination.

On the other hand, examples of the conjugated diene compound forming the polymer block B include butadiene, isoprene, piperylene, methylpentadiene, phenylbutadiene, 3,4
-dimethyl-1,3-hexadiene, 4,5-diethyl-1,3-octadiene, etc., among which butadiene and isoprene are particularly preferred. These conjugated diene compounds are 11! They may be used, or two or more types may be used in combination.

The method for producing this block copolymer is not particularly limited and any method can be used as long as the block copolymer having the above structure can be obtained. is used.

Examples of the (b) ethylene-based elastomer include TLF ethylene-propylene rubber, ethylene-propylene-nonconjugated diene rubber, ethylene-1-butene rubber,
Examples include ethylene-isobutylene rubber, polyimbutylene, ethylene-isobutylene rubber, and mixtures thereof. Among these rubber-like elastic bodies, ethylene-propylene rubber, ethylene-propylene-nonconjugated diene rubber, etc. are preferred.

The preferred ethylene-propylene rubber, ethylene-
As for the propylene-nonconjugated diene rubber, it is further preferable that the molar ratio of ethylene units to propylene units is in the range of 5=1 to 1:3.

The non-conjugated diene is selected from, for example, norbornene, liquid dienes, aliphatic dienes, etc., but 5-ethylidene-2-norbornene and dicyclopentadiene are preferred, and the proportion thereof is in the range of 40 or less in terms of iodine value. is preferred.

In addition, this ethylene elastomer has a muni viscosity (ML, +0100°C) of 10 to 100, particularly 20 to 100.
A range of 90 is preferred.

Further, as the polyolefin resin (c), for example, polypropylene, polyethylene, ethylene-α-olefin copolymer rubber, ethylene-α-olefin-nonconjugated diene compound copolymer (such as EPDM), ethylene-aromatic A monovinyl compound-conjugated diene compound copolymer rubber or the like is used. Further, as the σ-olefin, for example, propylene, butene-1, pentene-1,
Examples include 11hexene-L 4-methylpentene-1, and these may be used alone or in combination of two or more. Among these polyolefin resins, homopolypropylene is preferred.

Examples of unsaturated carboxylic acids or derivatives thereof used for modification include maleic acid, fumaric acid, itaconic acid, halogenated maleic acid, cis-4-cyclohexene-1,2
-dicarboxylic acid, endo-cis-bicyclo(2,2,1
) -3-Heptene-2,3-dicarboxylic acid and other unsaturated dicarboxylic acids, and their acid anhydrides, esters, amides, imides, etc., among which maleic anhydride is particularly preferred. One kind of these unsaturated carboxylic acids or derivatives thereof may be used, or two or more kinds thereof may be used in combination.

The modified copolymer as component (C) in the composition of the present invention is at least one base resin selected from the above (a) block copolymers, (b) ethylene elastomers, and (c) polyolefin resins. It can be produced by modifying the base resin by adding the above-mentioned unsaturated carboxylic acid or its derivative in a solution or melt state in the presence or absence of a radical initiator. There are no particular restrictions on the modification method used at this time, and various known methods can be used; however, the modified copolymer obtained may contain undesirable components such as gel, or its melt viscosity may increase significantly. Methods that result in poor workability are not preferred. A preferred modification method includes, for example, a method in which the base resin is reacted with an unsaturated carboxylic acid or a derivative thereof in an extruder in the presence or absence of a radical initiator.

The amount of the unsaturated carboxylic acid or its derivative added in the modified copolymer thus obtained is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of the base resin. From the viewpoint of coating properties of the composition, it is desirable that the amount is in the range of parts by weight. This amount of addition can be easily determined by a method using an infrared spectrophotometer, a titration method, or the like.

In the present invention, the modified copolymer of component (C) may contain the unmodified base resin as long as the amount of unsaturated carboxylic acid or its derivative is within the above range.

In the composition of the present invention, the modified copolymer as component (C) is added in an amount of 3 parts by weight based on 100 parts by weight of the total amount of the polypropylene resin as component (A) and the styrene resin as component (B).
It is necessary to mix in a proportion of ~35 parts by weight, preferably 5 to 30 parts by weight. If this amount is less than 3 parts by weight, the effect of improving paintability is insufficient, and if it exceeds 35 parts by weight, there is a tendency for rigidity and surface hardness to decrease.

In the present invention, in order to further improve secondary processability such as paintability, a styrene-based elastomer may be optionally blended as component (D).

As this styrene-based elastomer, for example, one consisting of at least one polymer block composed of aromatic vinyl compound units and at least one polymer block composed of conjugated diene compound units is used. The polymer block composed of diene compound units may be partially or entirely hydrogenated.

Examples of the monomer forming the polymer block composed of aromatic vinyl compound units include styrene and α-
Examples include alkylstyrenes such as methylstyrene, p-methylstyrene, and p-tert-butylstyrene, as well as p-methoxystyrene and vinylnaphthalene, among which styrene and p-methylstyrene are particularly preferred. One type of these aromatic vinyl compounds may be used, or two or more types may be used in combination.

On the other hand, examples of monomers that are composed of conjugated diene compound units and form polymer blocks include butadiene, isoprene, piperylene, methylpentadiene, phenylbutadiene, 3,4-dimethyl-1,3-hexadiene,
Examples include 4,5-diethyl-1,3-octadiene, among which butadiene and isoprene are particularly preferred. One type of these conjugated diene compounds may be used, or two or more types may be used in combination.

There are no particular restrictions on the method for producing the styrene elastomer of component (D), and conventionally known methods can be used, but an anionic polymerization method is preferable.

The blending amount of the styrene elastomer as the component (D), which is used as the case may be, is the same as the component (A), the component (B), and the component (C).
) The amount is selected in the range of 3 to 40 parts by weight, preferably 5 to 35 parts by weight, based on 100 parts by weight of the total amount of the components. If this amount is less than 3 parts by weight, the effect of improving paintability will not be sufficiently exhibited, and if it exceeds 40 parts by weight, there is a tendency for rigidity and surface hardness to decrease.

The polypropylene resin composition of the present invention is prepared by adding predetermined amounts of each of the components (A), (B), (C) and optionally used (D) to a Banbury mixer, 1 single screw extruder, etc. It can be prepared by kneading using a twin screw extruder, a co-kneader extruder, a multi-screw extruder, etc. at a temperature usually in the range of 180 to 240°C.

At this time, various known additive components may be added and kneaded as necessary within a range that does not impair the purpose of the present invention. Examples of the additive components include inorganic photonic agents such as calcium carbonate, talc, mica, silica, asbestos, glass beads, glass flakes, titanium oxide, alumina, quartz powder, and metal powder, glass fiber, carbon fiber, and metal whiskers. additives such as reinforcing agents, antioxidants, ultraviolet absorbers, heat stabilizers, mold release agents, lubricants, flame retardants, antistatic agents, and colorants, as well as other thermoplastic resins, rubbers, and elastomers. It will be done.

Effects of the Invention The polypropylene resin composition of the present invention has a polypropylene resin and a styrene resin as main components, and a specific modified copolymer and optionally a styrene elastomer are blended therein. The styrenic resin composition has a good balance of physical properties such as low-temperature impact resistance, surface hardness, and rigidity, and has significantly improved secondary processability such as paintability and adhesion, making it suitable as a material for interior and exterior parts of automobiles. used for.

Examples Next, the present invention will be explained in more detail with reference to examples.
The present invention is not limited in any way by these examples.

In addition, each characteristic of the composition was determined as follows.

(1) Paint film peel strength A test piece obtained by injection molding was coated with trichromitane for 3
After steam cleaning for 0 seconds and plasma treatment, urethane paint was applied to this, baked at 120°C for 30 minutes to form a coating film, and then heated at 23°C at a peeling rate of 5 hours.
A 180° peel test was conducted under the conditions of 1 cm width and 1 cm width to determine the coating film peel strength.

(2) Rockwell hardness (Idemitsu method) Using a test piece of thickness 31, length 70 ram, width 70 mm,
Standard load 10 to 9, test load 60hy, steel ball indenter diameter 1
The test was conducted under the conditions of 2-811111, and the Rockwell hardness (R scale) was determined.

(3) Flexural modulus It was determined in accordance with ASTM D-790.

(4) Izotsu impact strength (-30°C) JIS K-
7110.

In addition, the product name and properties of each component used are shown below.

(a) Block polypropylene manufactured by Idemitsu Petrochemical Co., Ltd., trade name J-750H, M ni 1
O(b) High impact polystyrene manufactured by Idemitsu Petrochemical Co., Ltd., trade name HT-51, MI:
2(C) Styrene-ethylene/butylene-styrene copolymer manufactured by Shell Chemical Co., Ltd., trade name Kraton G 1652 Styrene unit content: 29% by weight Number average molecular weight: approximately 50.000 Mw/Mn: 1. I A block molecular weight: 7,0QO B block molecular weight: 35.000 (d) Homopolypropylene manufactured by Idemitsu Petrochemical Co., Ltd., product name J-2000G, M
I: 20(e) Styrene-maleic anhydride copolymer manufactured by Idemitsu Petrochemical Co., Ltd., trade name UH-830, MI
: 1.5 (200°C 15 kg), maleic anhydride unit content 14 mol% (f) Nuthylene-butadiene copolymer manufactured by Shell Chemical Co., Ltd., trade name Cauliflex TRKX-
65S, MI: 6 (200°C/'5kg)
, styrene/butadiene (weight ratio) = 28/72 (g) Ethylene-propylene rubber manufactured by Japan Synthetic Rubber Co., Ltd., trade name EPO7P, Ml
: 0.7 (230°O/2.16kg), Mooney viscosity ML, Ya 4 (100°C) Near 0 Example 1 Block polypropylene r J -750HJ 85 parts by weight, high impact polystyrene FHT-51J 1
5 parts by weight and 2% by weight of maleic anhydride in styrene-ethylene/butylene-styrene copolymer r G 1652J.
using a twin-screw kneader at a temperature of 200°C and a rotation speed of 500 rpm to obtain pellets.
A test piece was made by injection molding, and each physical property was determined.

The results are shown in Table 1.

Example 2 The same procedure as in Example 1 was carried out except that the amounts of block polypropylene and high impact polystyrene were changed to 70 parts by weight and 30 parts by weight, respectively. The results are shown in Table 1.

Example 3 In Example 1, styrene-maleic anhydride copolymer rUH-830J was used instead of high impact polystyrene.
It was carried out in the same manner as in Example 1 except that . The results are shown in Table 1.

Example 4 The same procedure as in Example 1 was carried out except that the amount of the modified copolymer was changed to 25 parts by weight. The results are shown in Table 1.

Example 5 Example 1 was repeated except that 23 parts by weight of styrene-butadiene copolymer "Califlex TRKX-65SJ (20 parts by weight relative to 100 parts by weight of the composition of Example 1) was added. It was carried out in the same manner.

The results are shown in Table 1.

Example 6 The same procedure as in Example 1 was carried out except that 23 parts by weight of styrene-ethylene/butylene-styrene copolymer r G 1652J was further blended. The results are shown in Table 1.

Comparative Example 1 Comparative example 1 was carried out in the same manner as in Example 1 except that the modified copolymer was not blended.

The results are shown in Table 1.

Comparative Example 2 Comparative Example 1 was carried out in the same manner as in Comparative Example 1, except that 5 parts by weight of styrene-butadiene copolymer [Califlex TRKX-65SJ] was further blended. The results are shown in Table 1.

Example 7 Block polypropylene rJ-750HJ 85 parts by weight and high impact polystyrene rHT-51J 1
5M parts and ethylene-propylene rubber r EPO7PJ
Modified copolymer 15 with 2% by weight of maleic anhydride added to
parts by weight were kneaded using a twin-screw kneader at a temperature of 200'C and a rotation speed of 500 rpm to obtain pellets, and the pellets were then injection molded at 220°C to create test pieces. Each physical property was determined. The results are shown in Table 2.

Example 8 The same procedure as in Example 7 was carried out except that the amounts of block polypropylene and high impact polystyrene were changed to 70 parts by weight and 30 parts by weight, respectively. The results are shown in Table 2.

Example 9 In Example 7, styrene-maleic anhydride copolymer rUH-830J was used instead of high impact polystyrene.
It was carried out in the same manner as in Example 7 except that . The results are shown in Table 2.

Example IO Example 7 was carried out in the same manner as in Example 7, except that the amount of the modified copolymer was changed to 25 parts by weight. The results are shown in Table 2.

Example 11 In Example 7, styrene-butadiene copolymer [Califlex TRKX-65SJ 23 parts by weight (
The same procedure as in Example 7 was carried out except that 20 parts by weight of the composition of Example 7 was added. The results are shown in Table 2.

Example 12 In Example 7, the styrene-ethylene-butylene-styrene copolymer r c 1652. J231
The same procedure as in Example 7 was carried out except that M1kfA was added. The results are shown in Table 1g2.

Example 13 85 parts by weight of block polypropylene rJ-750H, 15 parts by weight of high impact polystyrene rHT-51J, and 15 parts by weight of a modified copolymer obtained by adding 2% by weight of maleic anhydride to homopolybrene rJ-2000GJ,
Using a twin-screw kneader, temperature 200'O, rotation speed 500r
After kneading under pm conditions to obtain pellets, the pellets were injection molded at 220° C. to prepare test pieces, and each physical property was determined. The results are shown in Table 3.

Example 14 The same procedure as in Example 13 was carried out except that the amounts of block polypropylene and high impact polystyrene were changed to 70 parts by weight and 30 parts by weight, respectively. The results are shown in Table 3.

Example 15 In Example 13, styrene-maleic anhydride copolymer rUH-830 was used instead of high impact polystyrene.
The off-site test using J was carried out in the same manner as in Example 13.

The results are shown in Table 3.

Example 16 The same procedure as in Example 13 was carried out except that the amount of the modified copolymer was changed to 25 parts by weight.

The results are shown in Table 3.

Example 17 Example 13 except that 23 parts by weight of the styrene-butadiene copolymer "Califlex TRKX-65SJ (20 parts by weight relative to 100 parts by weight of the composition of Example 13) was added. The results are shown in Table 3.

Example 18 The same procedure as in Example 13 was carried out except that 23 parts by weight of styrene-ethylene/butylene-styrene copolymer rG1652J was further blended. The results are shown in Table 3.

Claims (1)

[Scope of Claims] 1 (A) 60 to 95% by weight of polypropylene resin and (
B) For 100 parts by weight of the mixture with 5 to 40% by weight of styrene resin, (C) (i) a block copolymer of an aromatic vinyl compound and a conjugated diene compound, (b) an ethylene elastomer, and (c) A polypropylene resin composition comprising 3 to 35 parts by weight of a modified copolymer obtained by adding an unsaturated carboxylic acid or a derivative thereof to at least one selected from polyolefin resins. 2 With respect to 100 parts by weight of the resin composition according to claim 1, (
D) A polypropylene resin composition containing 3 to 40 parts by weight of a styrene elastomer.